HMB265H1 Lecture Notes - Lecture 4: Genetic Counseling, Generation Time, Consanguinity

• School: UTSG
• Department: Human Biology
• Course: HMB265H1
• Professor: Maria Papaconstantinou

Document Summary

Pedigrees aid the study of hereditary traits in human families. Humans are slippery genetic subjects: generation time too long, families produced are relatively small, mates not based on genetic considerations; no controlled matings, no pure-breeding lines. Pedigrees: family history; orderly diagram of family"s relevent genetic features. Vertical pattern of inheritance indicates rare dominant trait. Horizontal pattern of inheritance indicates rare recessive trait. In many cases, the affected individual is a product of a consanguineous. Autosomal traits located on non-sex chromosomes (1-22) Autosomal dominant: homozygous dominant and heterozygotes exhibit the affected phenotype, males and females equally affected and may transmit the trait, does not skip generations. Autosomal recessive: only homozygous recessive individuals exhibit the affected phenotype, males and females equally affected and may transmit the trait, may skip generations. Does it skip generations: no: dominant, yes: recessive. Are males and females equally susceptible: yes: autosomal, no: x-linked. Information provided on specific disorders, modes of inheritance, tests to identify at-risk family members.